The present invention relates to a system for managing a semiconductor fabrication device in a process line for fabricating semiconductors of liquid crystal substrates or the like.
In a process line for fabrication of semiconductors of liquid crystal substrates or the like, process control and quality control are important with view to improving a non-defective rate. For this purpose, when a failure occurs to the process line, data necessary for diagnosing causes of the failure have to be collected.
Conventionally, in a semiconductor fabrication process line, a checking process is provided for every several processes. Upon detection of a failure, all the processes on an upstream side to the checking process are subjected to inspection, to correct the failure. More specifically, the inspection is carried out by checking recording of a process time, a processing device, a processing chamber, a device alarm, etc. as history of the process until occurrence of the failure, by checking a state of a substrate therebefore and thereafter, quality control data, and device control data, by a hearing inspection to workers, by visual check upon maintenance, etc. Then, the failure is tentatively reproduced based on the inspection result so that a cause of the failure can be diagnosed.
It is difficult, however, to diagnose a cause of a failure that has suddenly occurred. This is because a sudden failure is not reproducible, thereby being scarcely reproduced in a reproduction test even under the same conditions.
Therefore, in a conventional semiconductor fabrication process line, permanent supervision by technicians has been required to carry out plasma visual check, signal check, condition check, robot action check, sound check, event list check, visual check of a substrate after processing (check after film formation), etc. to take precautions against a sudden failure. Upon occurrence of a sudden failure, the technicians have determined based on their expertise whether to adjust the fabrication device or to stop the fabrication device to carry out disassembly and maintenance of the fabrication device, to lower a rate of occurrence of a sudden failure.
Incidentally, the following Japanese Publications for Laid-Open Patent Applications should be noted, though their disclosures belong to fields different from that of the present invention.
The Japanese Publication for Laid-Open Patent Application No. 89285/1994 (Tokukaihei 6-89285 [Issue Date: Mar. 29, 1994]) discloses a process control system applied to spindle motor production process lines, in which defect input switches corresponding to defect items are provided and the fetching and totalizing of data is conducted in real time by a computer network. The foregoing process control system, however, only classifies and totalizes defects according to the defect items, and is incapable of diagnosing the causes of defects and the processes of occurrence of defects. Furthermore, it does not determine whether a product is defective or non-defective before an inspection process, and hence, cannot be applied to real-time checking.
The Japanese Publication for Laid-Open Patent Application No. 152789/1995 (Tokukaihei 7-152789 [Issue Date: Jun. 16, 1995]) discloses a plant analysis equipment diagnosis system for a manufacture process line in a steel plant. According to the foregoing system, without depending on the observer""s expertise, a state of a manufacturing apparatus is compared with time-sequential patterns assuming abnormal time, and when they are matched, a warning is outputted. The plant analysis equipment diagnosis system thus arranged predicts a danger leading to operation deterioration of a plant, and allows preventive maintenance to be carried out. However, the foregoing plant analysis equipment diagnosis system only prevents operation deterioration, and confirmation of normal operations, maintenance and management of normal quality of products, and diagnosis of a cause of an abnormal event are dependent on the observer""s expertise and data obtained through test operations. Adjustment of the plant is also dependent on the observer.
On the other hand, the aforementioned conventional method for managing semiconductor fabrication device has a drawback in that the cause of a sudden failure cannot be diagnosed. In other words, conventionally, serial control signals are not grasped in the fabrication process line for fabricating semiconductors of liquid crystal substrates and the like, and this makes it impossible to diagnose causes of sudden failures. Furthermore, since collation of a measurement sequence with a setting sequence regarding a fabrication device is not carried out or such collation is insufficient, the quality of products is not uniform, as well as sudden failures tend to occur. Furthermore, as described above, a rate of occurrence of sudden failures can be lowered by adjustment or maintenance of a fabrication device based on technicians"" expertise, but reasons for the lowering of the failure occurrence rate are left unknown.
Conventionally, regarding this problem, inspection has been made by using an adopted method, and adequacy of the adopted method has been inductively argued based on the result. In other words, a method has been induced from countermeasures applied in coping with similar irregular events in the past (from experiences), and if a result obtained was not satisfactory, overcoming the problem has been attempted by repeated trial and error.
An object of the present invention is to provide a management system for a semiconductor fabrication device capable of allowing a process line to stably operate as well as discovering a cause of a sudden failure.
To achieve the foregoing object, a management system for a semiconductor fabrication device in accordance with the present invention includes (i) a sensor for always collecting management information from a fabrication device provided in a semiconductor fabrication process line, and (ii) a determiner for monitoring the management information collected by the sensor as a time-sequential measured value pattern, and for comparing the measured value pattern with a set value pattern registered beforehand in accordance with the management information.
Furthermore, a semiconductor fabrication device management method in accordance with the present invention includes the steps of (a) monitoring management information collected by a sensor as a time-sequential measured value pattern, the sensor always collecting management information from a fabrication device provided in a semiconductor fabrication process line, and (b) comparing the measured value pattern with a set value pattern registered beforehand in accordance with the management information.
According to the foregoing system and method, to confirm states of the fabrication devices and the processing operation in the semiconductor fabrication process line, a variety of waveforms are collected at all times by means of sensors provided in respective fabrication devices, the sensors detecting management information such as a temperature, a moisture, a concentration, a pressure, a gas flow rate, electric power, sequence electric signals, mechanical electrical indices, etc.
Then, by the determiner, waveform data of the measured value pattern obtained are compared with waveform data of the set value patten registered beforehand in accordance with the management information. More specifically, a control start point is confirmed, and the measured value pattern is compared with the set value pattern, so that a deviation of the measured value pattern from the set value pattern is detected.
Thus, in the foregoing management system for a semiconductor fabrication device in which values measured by the sensors are always monitored in the form of time-sequential waveform data, when a sudden failure occurs, a cause, a time, relevance to another factor, a rate of occurrence, distribution of conditions of the occurrence, of the failure can be presumed data. This enables immediate discovery of the cause of the sudden failure, thereby ensuring that measures to cope with the failure can be taken immediately.
For instance, in the case where a failure occurs to the semiconductor fabrication device, it is also possible to stop the fabrication device by outputting a device stop signal to the fabrication device based on the result of comparison of the foregoing measured value pattern with the set value pattern. Here, along with graphs of sensor data, presumed causes of failure can be shown to workers in a descending order of probability thereof. It is also possible to show an inspection method and a determination method to the workers. In other words, not only the fabrication device in the fabrication process line can be stopped/replaced, but also a cause of the failure can be discovered by carrying out tests on factors presumed as causes of the failure in a descending order of probability. This results in efficient selection of measurement to cope with the sudden failure.
Therefore, according to the foregoing management system and method for a semiconductor fabrication device, an analysis scheme for low-cost production is efficiently suggested by using the sensor data of the fabrication device. Consequently, by applying adjustment and modification to the fabrication device to remove the cause of the failure, the fabrication process line can be stably operated, resulting in that a high yield is achieved.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.